1993 Toyota Corolla Speedometer Erratic

Try the vehicle speed sensor at the tranny

Any idea if this is a difficult part to replace? I assume it needs to be replaced from under the car. Thanks for the quick reponse

mine is doing the exact same thing. seems to have coincided with replacement of a dead alternator, but the two problems may be unrelated. alternator has been replaced but the speedo does EXACTLY what yours is doing.

I am in the process of getting the speed sensor replaced, used part off of EBAY since this part is nearly $200 new. Will let you know if this fixes the problem. Thanks!

Take it out-make sure its connected,cleaned-then turn key to On position and spin it-the speedometer should fluctuate, any wiggle will do-indicating its still good. No fluctutation= VSS or wiring problem, you might also have another one in the speedo head.Put it back in make sure its line properly and all the way in. Road Test.

Good Luck!

This was a job I won’t soon forget. I was unable to get the speed sensor out. Up about a quarter of a inch a best. So I just replaced the head of the full sensor unit. This is the piece that contains the circuit. Same results, bad speed readings. Had a buddy with one of the diagnosis units which indicated the sensor was reporting correctly. Actually had to drive with the diagnostic unit on my lap. I tried a different cluster unit with similar problems. Road Test, I think your assessment is correct, there must be wiring issues between the cluster and the sensor since the sensor must be giving the correct reading for the diagnostics to report the correct speed.

Not sure how to handle the wiring bit.

For those of you looking for where the speed sensor is on the 93 corolla, it is on top of the trans behind engine. Almost a perfect 12 o’clock position if you are standing in front of the car. You can only see it working for the right side of the hood.

Ok, since I am convinced that my speedometer problem is not the Speed Sensor and most likely not the Cluster that it must be the wiring. Since the diagnostics retrieved the correct speed readings, I can eliminate the wiring from the speed sensor.

So, this leaves me with the wiring from the cluster to wherever the hell it goes. Does anyone have suggestions to replacing/testing this portion of the wiring. I know very little about cars so be easy on me with the terms.

Thanks!

[quote:8cf196125a="lashark"]Ok, since I am convinced that my speedometer problem is not the Speed Sensor and most likely not the Cluster that it must be the wiring. Since the diagnostics retrieved the correct speed readings, I can eliminate the wiring from the speed sensor.

So, this leaves me with the wiring from the cluster to wherever the hell it goes. Does anyone have suggestions to replacing/testing this portion of the wiring. I know very little about cars so be easy on me with the terms.

Thanks![/quote:8cf196125a]

Here's the VSS configurations:

1. From tranny or transaxle Vss to ECM
2. " tranny or transaxle thru combination meter Vss to ECM
3. " tranny or transaxle Vss thru combination meter to ECM
4. from Wheel Speed Sensor to ABS computer thru combination meter to ECM

PCM/ECM/ECU=The Computer

Are most ECU's located behind the dashboard? I am hoping it is just the wire between the cluster and ECU. Sounds simple, I think

Not really familiar with that model-you said earlier you can track it with the scantool. Do you have a manual cause they are different configurations on how the speed sensors are wired and how many involved. I hope am right, you're looking for a Brn and white for the signal wire and a brown for a ground-that's coming from the speed sensor-dunno from the cluster to ecm might change color from there.

BTW how did you check the sensor-that you're getting the correct speed.

[quote:75d2513763="rasmataz"]Not really familiar with that model-you said earlier you can track it with the scantool. Do you have a manual cause they are different configurations on how the speed sensors are wired and how many involved. I hope am right, you're looking for a Brn and white for the signal wire and a brown for a ground-that's coming from the speed sensor-dunno from the cluster to ecm might change color from there.

BTW how did you check the sensor-that you're getting the correct speed.[/quote:75d2513763]

A buddy of mine has the "Snap-On" diagnositc unit. Normally when I drive, there is no reaction from the Speedometer until I hit about 40mph where then it jumps to 60 in reading. The Snap-on diagnositc unit showed differently. As I accelerated from 0 on up, the speed reading where correct.

So, this is why I have elimated the Speed Sensor, the ECU and the wiring between the Speed Sensor and the ECU. Last causes left are the cluster and the wiring from the cluster. I did change the cluster, possible the replacement is bad too, and saw simliar results. This leaves me with the wiring from the cluster to the ECU. Boy I hope it is easy as it sounds. LOL

Since I already replaced the cluster with a used one I purchased on EBAY I almost ruled this out as the problem. Only thing that made me second guess my assumption was the speedometer on the replacement cluster was not working the same way as the original cluster. It was somewhat similar but still erratic reading. This was enough that I ordered a third cluster. Well, this did the trick and all is working now. Glad I did it because the wiring going into some blue box in the dash looked chaotic.

Now with a different odometer reading, I guess I have to document the change with the different mileage reading.

Thanks for all the help gang!

Glad, you got it going again.
Good Luck!

[quote="lashark"]Since I already replaced the cluster with a used one I purchased on EBAY I almost ruled this out as the problem. Only thing that made me second guess my assumption was the speedometer on the replacement cluster was not working the same way as the original cluster. It was somewhat similar but still erratic reading. This was enough that I ordered a third cluster. Well, this did the trick and all is working now. Glad I did it because the wiring going into some blue box in the dash looked chaotic.

Now with a different odometer reading, I guess I have to document the change with the different mileage reading.

Don't forget to donate-maybe next time its nothing there to read. Its free99 who won't take advantage. It takes money to run this site.

Already donated via paypal but is not the same email link to this site. This site is very informative!

You can get a new one here for 50 bucks.
http://www.1aauto.com/speed-sensor/i/1atrs00131?f=449522&y=1993&utm_campaign=gb_csv_br&utm_content=TRS&gclid=CLDrn4jg_L8CFSMV7AodbBUA6A